Driving mechanism



March 2, 1943. MATHlEU I 2,313,001

DRIVING MECHANISM Filed Jan. 20, 1940 3 Sheets-Sheet l 2 fig? IFREDERICHBTHIEU March 2, 1943.

F. MATHIEU 7 2,313,001 DRIVING MECHANISM Filed Jan. 20, 1940 3Sheets-Sheet 2 mvEnToR= FREDERK: nmmsu BY: 551i (2 March 2, 1943.MATHlEU 2,313,001

DRIVING MECHANISM Filed Jan. 20, 1940 3 Sheets-Sheet 3 FRE'oEmc manna:yuan, fi 6;-

Patented Mar. 2, 1943 DREVING MECHANISM Frederic Mathieu, Paris, France;vested in the Alien Property Custodian Application January 20, 1940,Serial No. 314,811 In France February 18, 1939 8 Claims.

This invention is for improvements in or relating to driving mechanismfor cinematograph Maltese cross projectors and has for its principalobject to improve the luminosity of Maltese cross projectors byaccelerating the change of the film between two images withoutincreasing excessively the strains to which the film is subjected, northe stresses which are applied to the different parts of the mechanism.

t is known to accelerate the change of the film by increasing andreducing periodically the speed of rotation of the Maltese cross, eitherby means of elliptical gears or by means of a finger-carrying platedriven eccentrically for example by means of a slide and a slidingpiece.

It has also been proposed to apply force to the Maltese cross in anon-tangential manner or to use a Maltese cross with three arms.

These different devices have met with many mechanical difiiculties(vibrations, noise, rapid wear, and the like) and they have not hithertobeen capable of practical employment.

Among these devices, some comprise three rotating members, the parallelaxes of which are disposed in the same plane.

According to the present invention, such a mechanism is considerablyimproved by shifting one of the axes of rotation out of the plane of theother two.

The invention will be more particularly described with reference to theaccompanying drawings, in which:

Figures 1, 2, and 3 illustrate in section the arrangement of theessential members of the driving mechanism of a Maltese cross, the firstwith a finger-carrying plate rotating at constant speed (ordinaryMaltese cross) and the other two with a finger-carrying platealternately accelerated and retarded by an eccentric driving device bysliding piece and slide. The Figure 2 represents a known arrangement ofthese members and Figure 3 an arrangement having the axis displacedaccording to the invention.

Figures 4 and 5 are diagrams illustrating the advantages derived by thepresent invention and Figures 6 and '7 illustrate a modified form of thepresent invention.

Referring to the drawings, a Maltese cross I is indicated as beingrotated by a stud 3 about an axis 2 in the direction of the arrow F.

The stud 3 is carried by a plate 4 which in accordance with Figure 1 ofthe drawings is intended to be driven about the axis 5 at constant speedin the direction of the arrow F, whilst in the case of Figures 2 and 3the plate 4 is intended to be driven at a variable speed. To this end inaccordance with Figures 2 and 3 the stud 3 extends through the plate 4and the rear extremity thereof extends with a friction fit into acylindrical hole in a sliding'piece B. The piece 6 slides with slightfriction in a diametrically arranged groove formed in a plate keyed to aspindle 8 which rotates at constant speed in the direction of the arrowF". The spindle 3 is itself driven by a train of gears, not shown on thedrawings.

In Figure 2, which represents a known arrangement of these members, itwill be seen that the three parallel axes 2, 5 and 8 are arranged in theplane X, Y, for example in a vertical plane.

Figure 3 shows, on the contrary, according to the present invention, oneof the three axes, for example 8, displaced by a certain angle A withrespect to the other two.

The advantage of the arrangement illustrated in Figure'3 will beapparent from the diagrams which are given in Figures 4 and 5.

Figure 4 represents as a function of the time (or what is the samething, as a function of the angular position of the primary constantspeed driving spindle) and for the three devices represented in Figures1, 2 and 3, the speeds V1, V2, V3, and the respective accelerations A1,A2, A3 of the film during the rotation of the Maltese cross.

In Figure 4, V1 and A1 therefore represent the speed and theacceleration of the film in the case of Figure 1, that is to say, for anormal Maltese cross without accelerator device.

In the same figure, V2 and A2 represent the speed and the accelerationof the film in the case of the arrangement illustrated in Figure 2, thatis to say, with a Maltese cross accelerated but without theaxis'being'displaced. It will be seen that the speeds and theaccelerations, that is to say, the forces exerted on the film, haveconsiderably increased, which is highly injurious for this latter,

In the same figure, V3 and A3 represent the speed and the accelerationof the film with an arrangement made in accordance with the presentinvention (Figure 3) that is, with Maltese cross accelerated and withdisplacement of the driving axes.

It will be noted from the diagrams:

1. That each starting with an arrangement made in accordance with thepresent invention is not so sudden, not only as compared with anordinary accelerated Maltese cross but even with an ordinary Maltesecross. This fact is indicated by the inclination of the curves of speedand of accelerations corresponding to the starting point, that is tosay, at 0.

2. That the maxima positive speeds and accelerations are much less withan arrangement made in accordance with the present invention than withan ordinary accelerating Maltese cross and are scarcely greater thanwith the normal Maltese cross.

3. That the maximum of negative acceleration becomes, on the contrary,much more marked with an arrangement made in accordance with the presentinvention. But it should be pointed out that this negative accelerationcorresponds to the stoppage of the film, which is helped by all thefrictional forces acting on the film, in particular in the projectionpassage Way, in such a manner that no fatigue results from the latter.It can also be noted in this respect that a device with a'displaced aXisin accordance with the resent invention makes the curves V3 and A3unsymmetrical, that is, reducing the positive maximum of acceleration(which corresponds to a weaker tractive effort on the film) whilstincreasing to a corresponding extent the negative maximum which is notat all injurious.

This result will appear still more clearly on examining the three curvesE1, E2 and E3 of Figure 5 and representing respectively the effortswhich the film actually undergoes with the devices illustrated inFigures 1, 2 and 3, taking into account its friction assumed to beconstant and equal to C, in the projection aperture.

As for the speeds on the preceding curves, it will be seen that theefforts E3 according to the proposed device are hardly greater than withan ordinary Maltese cross (E1) but that they are much less than with aMaltese cross accelerated without displacement (E2).

Actually the advantage due to the present invention is probably stillgreater than is shown on these curves owing to the fact that thefriction of the film in the projection aperture is not constant butundoubtedly a little greater at the moment of detachment produced ateach start, that is about the point 0. The smoother start of. the curvesV1, A1 which has been pointed out abovehas therefore in reality a verygreat significance.

Figures 6 and '7 finally show by way of nonrestrictive example, oneembodiment of a Maltese cross mechanism, accelerated and with displacedaxis according to the present invention. The description of thesefigures will indicate certain details of construction which have provedto be very important in the operationof such an apparatus.

Figure 6 illustrates in partial longitudinal section on two parallelplanes a Maltese cross mechanism, accelerated and having a displacedaxis in accordance with the present invention, that is, according to thediagrammatic illustration in Figure 3.

The greater part of Figure 6 is drawn in a vertical plane containing theaxis of the fingercarrying plate and the axis 8 of the slide plate. Thepart of the Figure 6 at the top and to the left is drawn in a planeparallel to the former but extending through the displaced axis of theMaltese cross. It is quite evident, in fact, that in practiceany desiredaxis could be displaced with respect to the plane of the other two.

The reference numerals employed in Figure 6 indicate correspondingmembers in Figures 1, 2 and 3. Thus, i represents the Maltese crosswhich is driven by the finger or stud 3 mounted on the plate 4 of thevariable speed spindle 5. The plate i is driven by the sliding piece 6and preferably by the extremity of the stud 3 which extends through theplate 4 or by an extension of the stud 3 from the other side of theplate. It is advisable, in fact, in order to reduce the stresses and thevibrations, to bring together as closely as possible the points ofapplication of the driving and resisting efforts which are applied tothis intermediate part. The sliding piece 6 into which the extremity ofthe stud 3 extends is driven by the plate 9 having a diametricallyarranged slide groove, on the driving spindle 8. Owing to the fact thatthe axes 5 and 3 are not in line, a uniform movement of the spindle 8results in a movement of the spindle 5 which is alternately acceleratedand retarded.

A pinion H drives the spindle 8 but the remainder of the drivingmechanism is not shown.

A flywheel l is rigidly fixed on to the plate of the spindle 8 and theshape and particular arrangement thereof in the interior of themechanism will be noted. The applicant has, in fact found that in orderto obtain the maximum efliciency and to achieve the greatest possiblesmoothness in running of the whole system, the flywheel I must be soarranged that its moment of inertia acts appreciably in the mean planeof the plate 4, which plane is shown diagrammatically by ZZ on Figure 6.

The axis 5 of the plate 4 is then preferably arranged on the same sideas the Maltese cross with respect to this plate, which arrangement issomewhat important.

A frame I2 which supports the mechanism will preferably be sufficientlyrobust in order to offer a sufiiciently great inertia againstvibrations.

The flywheel 7 is preferably made of bronze in order to have a largemass in a reduced volume.

The groove plate 9, like the spindle 8, the stud 3, and the majority ofthe parts of the mechanism, are made in steels of suitable kind andtemper. The locking slope lil of. the Maltese cross is, as usual, ofcast iron.

The sliding piece 6 is preferably of celeron a material often used forhigh speed gears, or of some similar material which has both theproperty of being very resistant to wear and of dampening in a veryefiicient manner vibrations, in consequence of great internal dampening.

Finally, it will be noted that there are shown on Figures 6 and 7certain particular lubricating devices which have been found veryefficient for the good operation of the mechanism forming the object ofthe invention.

Thus, the spindle 5 is hollow over a portion of its length in order tobring the oil under pressure directly on to the locking slope of theMaltese cross through the medium of a radial conduit made in the core ofthis slope.

The oil under pressure delivered at l! to the frame of the apparatus,collects first of all in a collecting chamber l3 from whence itpenetrates into the hollow axis 5 through the holes I4. It thus passesat [5 to the locking slope of the Maltese cross and at It opposite thesliding piece 6.

Figure 7 shows in particular the delivery of oil under pressure at IE onto the locking slope. The presence of this oil under pressure at themoment when the two surfaces come into contact forms a dampening cushionwhich greatly improves the smoothness of running.

It must be understood that the mechanical arrangements which are shownwith reference to Figures 6 and 7, are applicable not only toaccelerated Maltese cross arrangements, with displacement of the drivingaxes (according to Figure 3), but also to Maltese cross devices simplyaccelerated but without displacement of axis (Figure 2), and even as thegreater part of them, to ordinary Maltese cross devices (Figure 1).

What I claim as my invention and desire to secure by Letters Patent ofthe United States is:

1. In a film conveying device for cinematograph projectors having aMaltese cross, a driving finger, a finger-carrying plate having alocking slope, the combination of a slide groove plate of relativelygreater diameter than that of said finger-carrying plate and the latterplate being at least for the most part disposed within the area oroutline of the slide groove plate, an elongated sliding piece in theslide groove of the plate engaging the finger of the finger-carryingplate, a driving spindle of the slide groove plate operable at constantspeed, one of the three axes of the Maltese cross, of thefinger-carrying plate and of the slide groove plate being disposedexternally of the plane of the other two axes, and the finger-carryingplate being distinct from the Maltese cross and the elongated slidepiece and disposed in a plane intermediate said Maltese cross and slidepiece.

2. In a film conveying device for cinematograph projectors having aMaltese cross, a driving finger, a finger-carrying plate having alocking slope, the said finger-carrying plate being driven directly bythe extremity of the finger of the Maltese cross which is extended tothe other side of the said finger-carrying plate, the combination of aslide groove plate of relatively greater diameter than that of saidfinger-carrying plate and the latter plate being at least for the mostpart disposed within the area or outline of the slide groove plate, andelongated sliding piece in the slide groove of the plate engaging thefinger oi the finger-carrying plate, a driving spindle of the slidegroove plate operable at constant speed, one of the three axes of theMaltese cross, of the finger-carrying plate and of the slide grooveplate being disposed externally of the plane of the other two axes, andthe fingercarrying plate being distinct from the Maltese cross and theelongated slide piece and disposed in a plane intermediate said Maltesecross and slide piece.

3. In a film conveying device for cinematograph projectors, having aMaltese cross, a driving finger, a finger-carrying plate having alocking slope, the said finger-carrying plate being driven directly bythe extremity of the finger of the Maltese cross which is extended tothe other side of the said finger-carrying plate, the combination of aslide groove plate of relatively greater diameter than that of saidfinger-carrying plate and the latter plate being at least for the mostpart disposed Within the area or out- 1ine of the slide groove plate, anelongated sliding piece in the said slide groove carrying the axis ofthe finger-carrying plate, a driving spindle of the slide groove plateoperable at constant speed, one of the three axes of the Maltese cross,of the finger-carrying plate and of the slide groove plate beingdisposed externally of the plane of the other two axes, and the axis ofthe fingercarrying plate being arranged on the same side of the saidplate as the axis of the Maltese cross, and the finger-carrying platebeing distinct from the Maltese cross and the elongated slide piece anddisposed in a plane intermediate said Maltese cross and slide piece.

4. In a film conveying device for cinematograph projectors having aMaltese cross, a driving finger, a finger-carrying plate having alooking slope, the said finger carrying plate being driven directly bythe extremity of the finger of the Maltese cross which is extended tothe other side of th said finger-carrying plate, the combination of aslide groove plate and an elongated movable slide piece, said fingeralso extending into said movable slide piece in a diametrical slidegroove of said slide groove plate integral with the driving spindle ofconstant speed of the whole system, said slide groove plate being ofrelatively greater diameter than that of said finger-carrying plate andthe latter plate being disposed at least for the most part within thearea or outline of said slide groove plate, and one of the three axes ofthe Maltese cross, of the finger-carrying plate and of the slide grooveplate being disposed externally of the plane of the other two axes, andthe fingercarrying plate being distinct from the Maltese cross and theelongated slide piece and disposed in a plane intermediate said Maltesecross and slide piece.

5. In a film conveying device for cinematograph projectors, having aMaltese cross, a driving finger, a finger-carrying plate having alocking slope, the said finger-carrying plate being driven directly bythe extremity of the finger of the Maltese cross which is extended tothe other side of the said finger-carrying plate, the combination of aslide groove plate and an elongated movable slide piece, said fingeralso extending into said movable slide piece in a diametrical slidegroove of said slide groove plate integral with the driving spindle ofconstant speed of the whole system, said slide groove plate being ofrelatively greater diameter than that of said finger-carrying plate andthe latter plate being disposed at least for the most part Within thearea or outline of said slide groove plate, and one of the three axes ofthe Maltese cross, of the finger-carrying plate and of the slide grooveplate being disposed externally of the plane of the other two axes and aflywheel integral with the slide groove plate and having the drivingspindle arranged about the finger-carrying plate, and thefinger-carrying plate being distinct from the Maltese cross and theelongated slide piece and disposed in a plane intermediate said Maltesecross and slide piece.

6. In a film conveying device for cinematograph projectors having aMaltese cross, a driving finger, a finger-carrying plate having alocking slope, the said finger-carrying plate being driven directly bythe extremity of the finger of the Maltese cross which is extended tothe other side of the said finger-carrying plate, the combination of aslide groove plateand an elongated movable slide piece, said finger alsoextending into said movable slide piece in a diametrical slide groove ofsaid slide groove plate integral with the driving spindle of constantspeed of the whole system, said slide groove plate being of relativelygreater diameter than that of said finger-carrying plate and the latterplate being disposed at least for the most part within the area oroutline of said slide groove plate, and one of the three axes of theMaltese cross, of the finger-carrying plate and of the slide grooveplate being disposed externally of the plane of the other two axes and aflywheel integral with the slide groove plate and having the drivingspindle arranged about the fingercarrying plate, the finger, thespindles and the slide groove being formed of steel, the flywheel ofbronze and the sliding piece of celeron or similar material, and thefinger-carrying plate being distinct from the Maltese cross and theelongated slide piece and disposed in a plane intermediate said Maltesecross and slide piece.

'7. In a film conveying device for cinematograph projectors having aMaltese cross, a driving finger, a finger-carrying plate having alooking slope, the said finger-carrying plate being driven directly bythe extremity of the finger of the Maltese cross which is extended tothe other side of the said finger-carrying plate, the combination of aslide groove plate and an elongated movable slide piece, said fingeralso extending into said movable slide piece in a diametrical slidegroove of said slide groove plate integral with the driving spindle ofconstant speed of the whole system, said slide groove plate being ofrelatively greater diameter than that of said finger-carrying plate andthe latter plate being disposed at least for the most part within thearea or outline of said slide groove plate, and one of the three axes ofthe Maltese cross, of the finger-carrying plate and of the slide grooveplate being disposed externally of the plane of the other two axes and aflywheel integral with the slide groove plate and having the drivingspindle arranged about the fingercarrying plate, the finger, thespindles and the slide groove being formed of steel, the flywheel ofbronze and the slide piece of celeron or similar material and therebeing means for applying lubrication under pressure to the mechanism inparticular to the locking slope of the Maltese cross, and thefinger-carrying plate being distinct from the Maltese cross and theelongated slide piece and disposed in a plane intermediate said Maltesecross and slide piece.

8. In a film conveying device for cinematograph projectors having aMaltese cross, a driving finger, a finger-carrying plate having alooking slope, the said finger-carrying plate being driven directly bythe extremity of the finger of the Maltese cross which is extended tothe other side of the said finger-carrying plate, the combination of aslide groove plate and an elongated movable slide piece, said fingeralso extending into a movable slide piece in a diametrical slide grooveof said slide groove plate integral with the driving spindle of constantspeed of the whole system and said slide groove plate being ofrelatively greater diameter than that of said finger-carrying plate andthe latter plate being disposed at least for the most part within thearea or outline of said slide groove plate, and a flywheel integral withthe slide groove plate and with the driving spindle being arranged aboutthe finger-carrying plate, the finger, the spindles and the slide groovebeing formed of steel, the flywheel of bronze, and the sliding piece ofceleron or similar material, and the finger-carrying plate beingdistinct from the Maltese cross and the elongated slide piece anddisposed in a plane intermediate said Maltese cross and slide piece.

FREDERIG MATHIEU.

